The objective of this proposal is to localize genetic traits to specific human genetic linkage groups resulting in increased information on the nature of human gene map. Families which have been studied for the segregation of selected genetic disorders will be investigated by analyzing genetic expressed phenotypes in the blood to determine if the genetic trait and various marker loci segregate dependently or independently. Those loci whose segregation is dependent, rather than independent, are inferred to be linked as a result of these close physical localization to a common segment of DNA. The distance apart between the loci is measured by the recombination fraction as a result of greater crossing over in the distance between loci that are farther apart. By detecting linkage groups, loci can be assigned to chromosomal regions and the localization of genes producing hereditary disorders will increase our knowledge of the human genetic map. The knowledge of gene order will be useful in understanding the pathogenesis of many inherited disorders and will be necessary for investigations in the future which are designed to cure genetic diseases.